John blake tare



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mw-eser@ --W- JoHN BLAKE TARR, or FAIR HAVEN, MASSACHUSETTS. y Leners Petn: No. 83,224, met Gamba 20, 1868. l

IMPROVEMENT IN STEAM-ENGINES.

The Schedule referred to in these Letters Patent and making part. of the same.

To all whom at ma/y concern.-

Beit known that I, J OHN BLAKE TARE, of Fair Haven, in the county of Bristol, and State of Massachusetts, have invented a new and useful Improvement in Steam-Engines; and I do hereby declare that the following is afull, clear, and exact description thereof, reference being had to the accompanying drawings, making a pait of this specification, in which- Figure l is a perspective view of a horizontal engine and steam-boiler, showing a pump, which is worked by the engine, applied to a -steam-superheating supplypipe leading from said pump to the engine.

Figure 2 is a plan view of the same parts, with a portion of the steam-boiler broken away over the furnace-chamber, to show the arrangement of steamsuperheating pipe therein.

Figure 3 is a vertical section through the pump, to which thesteam-superheating supply-pipe is connected.

Similar letters of reference indicate corresponding parts in the several figures.v

The object of this invention is to provide means whereby an engine can berun by steam at high pressure, while the steam in the boiler is maintained at a considerably lower pressure, by which the danger of boiler-explosions, caused by carrying too great a pressure of steam in them, can be guarded against.

In order to carry out this object, my invention consists essentially in conducting steam, on its way from a boiler to the steam-chest of an engine, through a pump which is worked by such engine, and thence passing the steam through a superheater, thereby re- `heating and increasing the elasticity or pressure of the steam after it leaves the boiler, and while'it is cut off from the boiler by the pump.

And, in combination with such means, the invention further consists in making provision for conducting steam directly from the boiler into the steam-chest of the engine, when it is desh'ed to start the engine and the pump, as will be hereinafter explained.

To enable others skilled in the art to understand my invention, I will describe one practical mode of carrying it into effect. y

'The drawings, iigs. l and 2, represent my invention applied toa well-known form of horizontal stationary engine and steam-boiler. But in order that my invention may be fully understood, I will briefly describe the several parts of said engine and boiler, in connection with the means employed for superheating steam taken fromV the' boiler.

G represents the frame or bed of the engine, and F the steam-cylinder, in which works a piston, the rod f of which is connected to a cross-head, g, that slides on ways G if, and communicates motion to .the ilywheel shaft l), through the connecting-rod-H and crankarm H. The shaft b has its bearings h1 pillow-blocks b J, and'carries an eccentric, c, for communicating motion to the slide-valve in valve-chest E, which it does through the-medium of pitman-rod c, crank-arms c2 and g2, shaft h, and valve-rod g1.

The steam-boiler A, which may be of any of thewell-known 'varieties, is mounted over a furnace, and provided with a steam-pipe, O, which leads from the steam-dome A into the, valve-chest E of the engine. The hand-wheel q is connected to a valve, which isy designed for shutting offl the direct communication of the valve-chest with the boiler when the engine is run by steam of higher pressure than that in the boiler.

A pipe', l), which is provided with a valve, al, takes steam from the pipe C, When the valve in this pipe is closed, and conducts it into a valve-chest, e, of a pumpcylinder, S. This steam is then alternately drawn through valves, it, by the movements of a doubleacting piston, l, and forced through valves, yy, into a steam-chest, n. The steam, which is forced into the chest n of the pump, escapes into a pipe, D', which enters the" hre-chamber under the steam-boiler and over4 the grate, and is thence carried to the valve-chest E of the engine, as shown in figs, l and 2.

After' the pipe. D leaves the valve-chest nof the pump, it is coiled over the furnace, so that a great length of it lwill be exposed to the direct heat of the lire, for the `purpose of subjecting the steam, as it passes from the pump on its way to the engine, to such a degree of heat as will render it more highly elastic than the steam in the boiler, in which condition it operates to work the engine.

The piston-rod p of the pump-piston is connected to. a cross-head, J 2, working upon suitable guide-ways, J3 J 3, and the piston of the pump receives its motions yfrom the ily-wheel shaft b of the engine, through the medium ofa crank-arm, b2, and connecting-rod, J as shown in figs. l and 2.

The valves of the double-actingforcing-pump are so arranged and applied tothe steam-chambers of this pump, that, when one induction-valve' is allowing steam from the boiler to enter the pump-cylinder on one side of the piston, the eduction-valve on the opposite'side of the pistou is allowing steam to be forced by this piston into the superheating-steam pipe D. Thus it will be seen that the two sets of valves of the pump, andthe piston thereof, serve as out-offs for preventing the press'ure of the superheated or high steam om reacting upon the boiler, which should contain stea at a comparatively low pressure.

In order to start the engine and pump, the valves a and l are shut, and the valve q opened, so as to opcrate at first with low-pressure steam taken directly Afrom the boiler through the steam-pipe C. During this operation the pump-cylinder S should be in communication with the atmospheric air, to allow the piston of this pump to work freely. Whentheengine and pump are started, the valves d and a are opened rand valve q closed, which causes all the steam from the boiler to pass through the pump and through the superheating-eoils of pipe D on its way to the valvechest E of the engine.' The power for operating the pump is derived from fthe engine, and also from the pressure of steam acting from the boiler.

I do not confine my invention to the particularkind 'of engine and boiler herein shown and described, nor

from the boiler by the action ofthe pump, substantially as described.

2. A pipe or pipes leading from a steam-boiler to the valve-chest of lan engine through a furnace, and provided with a forcing-pump, which is operated by said engine, substantially as described.

3. In combination with a steam-pipe, C, leading direct'from a boiler to an engine, and provided with a cut-off valve, I claim the means for taking steam from said pipe, C, superheating it, and theneonducting the superheated steam to the valve-e-hest of said engine, substantially as described.

Witnesses: l JOHN BLAKE TABR.

R. T. CAMPBELL, J. V. CAMPBELL.' 

